This invention relates to maintenance systems and, in particular, to cable restoration systems for temporarily restoring service to customers whose central office cable has been damaged.
Various restoration systems have been utilized to restore service to customers after their central office cable has been damaged by fires, floods, or other disasters. These systems typically utilize neon bulbs or light-emitting diodes that are connected to the ends of a cable break and operate as follows: When a customer goes off-hook to request service, the indicating device connected to his line is illuminated by means of battery power supplied at the cable break. A maintenance man operating the system then connects to the indicated line and asks the customer his directory number. After receiving the number, the maintenance man contacts a lineman at the central office and requests ringing on the line which corresponds to the customer's number. When ringing is applied to the proper line, the indicating device (associated with the line) lights and identifies the line to the maintenance man located at the cable break. The wires which are thereby identified may be spliced together to provide temporary service of the customer until a permanent splice in the cable can be made.
In this type of system, neon bulbs are typically used on the central office side of the break because such devices are inexpensive and respond directly to central office ringing to provide a visual indication. However, when neon bulbs are used to identify the central office lines, the assistance of a lineman at the central office is required to distinguish the identifying ringing from ringing caused by normal incoming calls. The central office will, in the normal course of operations, attempt to complete incoming calls to customers whose service has been impaired by the broken cable. In the process, the central office will apply ringing to the line. This ringing will, of course, be applied in the normal on and off cyclic pattern; therefore, in order to distinguish the desired line from other lines which may be illuminated by incoming ringing, the lineman in the central office must manually apply distinctive ringing (a different on and off pattern alternately to the tip and ring sides of the line or some other variation). The restoration operation therefore requires at least two maintenance personnel and is therefore cumbersome and expensive.
It is apparent that there is a need for a cable restoration system which can be operated by maintenance personnel located only at the cable break and which does not require the assistance of maintenance personnel at the central office.
Accordingly, it is an object of the present invention to identify a desired central office conductor without the assistance of maintenance personnel in the central office.
It is a further object of the present invention to perform identification of the central office line without using expensive circuitry at the cable break location.